Power conversion circuits are typically packaged together in a single circuit assembly that has static magnetic properties and is completely replaced when component failure occurs. In addition, volume and power density are properties of electronic circuits have become increasingly important as size of electronic devices has been reduced. U.S. Pat. No. 7,236,086 to Vinciarelli et al. describes a power conversion apparatus with primary and secondary circuit assemblies that are enclosed in mechanically separate protective housings and are magnetically coupled via transformer windings installed in each of the protective housings.